Flue plug



FIG. 1 is a top perspective view of a flue plug according to my new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is the front elevation view thereof;

FIG. 6 is a rear elevation view thereof;

FIG. 7 is a left elevation view thereof; and,

FIG. 8 is a right elevation view thereof.

The broken lines in FIGS. 1-8 illustrate portions of the flue plug that form no part of the claimed design. 

CLAIM The ornamental design for a flue plug, as shown and described. 